This invention relates generally to detection of deformations in the form of dings on sheet metal surfaces, and, more particularly, to detect a nature of the detected ding.
Manufacturing operations involving sheet metals based materials, panels or products, are observed to have undergone considerable advances and improvements over the years. During the manufacturing operations on sheet metals, however, certain undesirable visual deformations are observed on the sheet metal surfaces before the product's completion. Some of these deformations are classified as burrs, wrinkles, slivers, and other visual surface defects, caused possibly because of die and/or tool defects. Out of these, some defects are classified as dings, which are witnessed in a substantial amount by shop floor technicians working on the sheet metal based products. In certain cases, the sheet metal dings found may be as high as 60-65% out of all the defects encountered. Ding formations on sheet metal surfaces, therefore, form a major portion of defects found during a conventional sheet metal manufacturing operation, causing excessive inventory and repair, or even rejection of the sheet metal product, at times.
Conventionally, detection of such dings includes a process of swiping the sheet metal surface with a screening material. In general, all sheet metal surfaces, when detected with dings, are either rejected or carried away for repairs without considering their affect on the final product. A relatively large percentage of dings detected through the above noted method, in contrast, include a considerable variation in their physical sizes and dimensions. Accordingly, dings detected having considerably small dimensions may not affect a final work output, after a paint job, and thus may not be sent for repairs. Moreover, experiments have substantiated that a ding detected through the above process, but having a dimension less than a particular predetermined calculated value or standard, need not be seen as one that requires a repair. This, in general, is observed to be true once the related sheet metal product is formed into a final product and paint is applied to it.
There thus remains room for improvements in reducing the number of sheet metal rejections, thereby minimizing needless inventory and stock, repairs on which may not particularly affect the final work output.